mice analysis meeting alain blondel 5 august 2005 1 mice -- what running strategy? disclaimer: of...

1MICE analysis meeting Alain Blondel 5 August 2005

MICE -- what running strategy?

disclaimer: of course we will evolve the running strategy as problems arise;nevertheless think about it ahead of time to set goals to be achieved raise issues that influence some design featuresThe discussion here is triggered by the need to engineer the diffuser.


- STEP I:

April 2007

STEP II: October 2007

STEP III: 2008

STEP IV: 2008

STEP V2008?

STEP VI 2009?2009?

PHASE I

PHASE II


- STEP 1

STEP 2

STEP 2.5

Insert absorber (solid) between the two halves and measure pt & E distribution and emittance change Publishable result!

STEP 2.6

Split tracker in two parts and measure against each other(systematics)

Establish beam match andwhether we have all knobs necessary to draw emittance vs. transmission curve. Measure emittance

These are mostly questions for beam design and matching to and within solenoid.

I will not consider this for now


Step 1 and 2 already require from the beam line to have the basic knobs

beam aligned? question 1: how well should the <x> <x’> and <y> <y’> be =0 for beam to be considered aligned? beam matched? we will want to generate matched beam: x

2 = x’

2 =

with no dispersion, but perhaps a particular relation between amplitude and energy question 2: what precision is needed on this match to satisfy cooling measurements? question 3: can the beam gnerate the energy-amplitude relation or should the analysis do it?

beam intensity? (target tuning) many knobs to scan for a given diffuser setting. what precision needed how many muons will be needed to do this?

Once the baseline setting is matched and understood, will want to repeatexercize for various momenta and various diffuser to check that we can really generate all beams we need/want from 1 to 10 mm emittance.


We will also need data to do the initial alignment/calibration/characterization of the beam. Without and with mag field, vs momentum etc…

I think the detector experts should think about it and define their needs.

Do we need for instance a beam with small momentum spread? Do we need a beam enhanced in electrons or pions in order to tune up the PID detectors?

We will also need to establish the beam momentum scale …


step 3

from step3 onwards, we will also go through changes of MICE opticsand from step 4 onwards we will go through changes in absorbers.

A first study of the number of points and changes was made by Rob Edgecock at the collaboration meeting 5 (CERN; March 2003)

The only change to his list would be that we may need to scan both over

-- nominal momentum of MICE optics -- beam central momentum.

ex: if MICE is set to cool best at 200 MeV/c (i.e. MICE magnets set to this momentum) we may need to run central beam momentum at(i.e. beam magnets set to)e.g. 160, 200, 240 MeV/c

to cover well the momentum width of a real beam, or the amplitude momentum correlations etc..


Putting that togetherPutting that together

Runs = targets x RF voltage x Runs = targets x RF voltage x emittance emittance x momentum x betax momentum x beta

= 6 + 7 x 4 x 10 x 5 + 1 = 6 + 7 x 4 x 10 x 5 + 1 x 6 + 1 x 6 + 1 = 21840!= 21840!

•• Do only 3 RF voltagesDo only 3 RF voltages = 16380= 16380

•• Can do everything only for 3 targets: Can do everything only for 3 targets: LH2, LH2, LiHLiH, Li , Li = 3780= 3780

•• Scan all parameters all other targets Scan all parameters all other targets = 33 + 110 + 66 + 77= 33 + 110 + 66 + 77= 286 = 286

Total = 4066 runsTotal = 4066 runs= 18 months= 18 months

from Rob Edgecock

add beam momentum with three points and end up with 65600 points.

it is clear that some paramenters need to be factorized (RF volts for instance?)


the next question to understand is how to nest these loops (which do we do more often, which less)

here the following questions arise:

-- how bad is it to modify the MICE optics settings, with very large forces at play? should we thrive to minimize how often we do it?

-- does a change in beam momentum require a change in diffuser?

-- does a change in beam momentum require a whole cycle of 1. beam tuning 2. beam magnet cyclinghow long would this take and how reproducible can this be?

-- how long does it take to change the absorber?

-- how long does it really take to collect enough statistics?

the natural tendency would be to do what is written in proposal, i.e. to perform emittance scan for given MICE and beam settings. Is it true that this si probably the best thing to do from the point of view of systematics?


Given these uncertainties I would advocate that the absorber change over time should be as fast as possible, …unless some of the above questions have an obvious answer or that an answer can be given very soon.